TABLE 4.

Rates of WalR_Spn∼P dephosphorylation catalyzed by WalK_Spn in the presence of nucleoside phosphate cofactors^a

Cofactor (concn [μM])b	Mean ± SEM
	k (min−1)	WalRSpn∼P half-life (min)
1. None	0.0044 ± 0.00036	140 ± 10
2. ADP (13.2)	0.0195 ± 0.0002	34.5 ± 0.3
3. ADP, pH 7.8 (13.2)	0.029 ± 0.002	23.3 ± 1.9
4. ADP (120)	0.018 ± 0.0004	37.1 ± 0.9
5. ATP (13.2)	0.032 ± 0.006	21.3 ± 3.8
6. ATPγS (13.2)	0.019 ± 0.0001	35.4 ± 0.2

^aDephosphorylation rates and half-lives of WalR_Spn∼P were determined at 25°C in reaction mixtures containing Mg²⁺ at pH 7.4 (or pH 7.8 where indicated) in the presence or absence of cofactors as described in Materials and Methods. Reaction mixtures contained 5.9 μM WalR_Spn (N)-His∼P and 2.0 μM WalK_SpnΔN35 (C)-His. Experiments were performed independently twice.

^bSee Table 1, footnote b.